I remember reading a tech article somewhere that one of the RPM limiting factors on OLDS was the large size main journals because it builds up so much heat at higher RPM's. Maybe by turning them down, you can decrease the surface area somewhat, thus reducing heat. If you stick with the olds, I would most definately get a 10 quart oil pan, main restricters (from Mondello) and a oil cooler. Taylorman seems to be doing fine with his cut down crank.